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3 years ago

Hellllpppppppp helppppppppp

Chemistry

1 answer:

mixas84 [53]3 years ago

3 0

Answer :

Charles's Law : It is defined as the volume is directly proportional to the temperature of the gas at constant pressure and number of moles.

Mathematically,

$V\propto T$

Boiling water bath Cool bath 1 Cool bath 2

Temperature (⁰C) 99 17 2

Temperature (K)(T) 273+99=372 273+17=290 273+2=275

Volume of water 0.0 27.0 34.0

in cool flask (mL)

Volume of water= 135.8 135.8 135.8

Air in flask (mL)

Volume of air 135.8 108.8 101.8

in cool flask (V)

$\frac{V}{T}$ $\frac{135.8}{372}=0.365$ $\frac{108.8}{290}=0.375$ $\frac{101.8}{275}=0.370$

The graph volume versus temperature for a gas is shown below.

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calculate the number of moles of sulfuric acid that is contained in 250 mL of 8.500 M sulfuric acid solution

san4es73 [151]

Answer : The moles of $H_2SO_4$ are, 2.125 mole.

Explanation : Given,

Molarity of $H_2SO_4$ = 8.500 M

Volume of solution = 250 mL = 0.250 L (1 L = 1000 mL)

Molarity : It is defined as the number of moles of solute present in one liter of volume of solution.

Formula used :

$\text{Molarity}=\frac{\text{Moles of }H_2SO_4}{\text{Volume of solution (in L)}}$

Now put all the given values in this formula, we get:

$8.500M=\frac{\text{Moles of }H_2SO_4}{0.250L}$

$\text{Moles of }H_2SO_4=2.125mol$

Therefore, the moles of $H_2SO_4$ are, 2.125 mole.

5 0

2 years ago

How many grams of zinc would be required to produce 9.65g of zinc hydroxide

Effectus [21]

The question is incomplete, here is the complete question:

How many grams of zinc would be required to produce 9.65g of zinc hydroxide

Zn+2MnO₂+H₂O→Zn(OH)₂+Mn₂O₃

Answer: The mass of zinc required is 6.35 grams

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

Given mass of zinc hydroxide = 9.65 g

Molar mass of zinc hydroxide = 99.4 g/mol

Putting values in equation 1, we get:

$\text{Moles of zinc hydroxide}=\frac{9.65g}{99.4g/mol}=0.0971mol$

The given chemical equation follows:

$Zn+2MnO_2+H_2O\rightarrow Zn(OH)_2+Mn_2O_3$

By Stoichiometry of the reaction:

1 mole of zinc hydroxide is produced from 1 mole of zinc

So, 0.0971 moles of zinc hydroxide will be produced from = $\frac{1}{1}\times 0.0971=0.0971mol$ of zinc

Now, calculating the mass of zinc from equation 1, we get:

Molar mass of zinc = 65.4 g/mol

Moles of zinc = 0.0971 moles

Putting values in equation 1, we get:

$0.0971mol=\frac{\text{Mass of zinc}}{65.4g/mol}\\\\\text{Mass of zinc}=(0.0971mol\times 65.4g/mol)=6.35g$

Hence, the mass of zinc required is 6.35 grams

6 0

3 years ago

2Al + 6HCl → 2AlCl3 + 3H2 If 85.0 grams of HCl react, how many moles of H2 are produced?

Murrr4er [49]

Answer:

1.17 mol

Explanation:

Step 1: Write the balanced equation

2 Al + 6 HCl → 2 AlCl₃ + 3 H₂

Step 2: Calculate the moles corresponding to 85.0 g of HCl

The molar mass of HCl is 36.46 g/mol.

85.0 g × 1 mol/36.46 g = 2.33 mol

Step 3: Calculate the number of moles of H₂ produced from 2.33 moles of HCl

The molar ratio of HCl to H₂ is 6:3.

2.33 mol HCl × 3 mol H₂/6 mol H₂ = 1.17 mol H₂

8 0

2 years ago

A filament of a light bulb is made from a pure sample of tungsten.

GenaCL600 [577]

Answer:

The correct options are:

1) Pure chemical substance

2) Element.

Explanation:

each of the term is explained below:

1) Mixture: Since tungsten is an element in periodic table thus it is not a mixture.

2) False by definition of mixture.

3) false by definition of mixture.

4) Solution: Tungsten in a filament is in solid form hence solution is incorrect.

5) Since it is given in the question itself that the sample is pure hence option 'E' is correct as chemical substance is a pure substance that has a homogeneous composition and the sample in the question is given as pure.

6) Compound: By definition of compound it is formed by mixing 2 or more elements but since tungsten is an element that occurs independently in nature hence it is not a compound.

7) Tungsten is a element in the periodic table with atomic number 74.

8 0

3 years ago

Calculate the fraction of lattice sites that are schottky defects for cesium chloride at its melting temperature (645oc). assume

baherus [9]

Answer : 7.87 X $10^{-6}$ .

Explanation : To find the fraction of schottky defects in the given lattice of CsCl,

we use the formula, $\frac{N_{s} }{N}} = exp ( \frac{-Q_{s}}{2KT} )$

on solving with the given values , $Q_{s}= 1.86 eV$ and T as 645 + 273 K and rest are the constants.

$\frac{N_{s} }{N}} = exp ( \frac{-1.86 eV}{2 X (8.62 X 10^{-5}) X (645 +273)} )$

we get the answer as 7.87 X $10^{-6}$ .

6 0

3 years ago

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